Emental: The Series

An alien named Necrosse is suddenly given two missions by his captain: First, he is to go to Earth and apprehend a legendary emental named Excalibur for an undisclosed reason, and second, to
release a bio-weapon upon the population which inflicts a zombie-like state. However, when Necrosse and his artificial bio-weapon personality arrive on Earth, they realize apprehending Excalibur is
going to be harder than anticipated. Meanwhile, the lives of 2 teenage humans, and 1 teenage emental, is turned upside down when an alien shows up and causes the end of the world.